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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'fd5487a51cc0ffb16de7d120366e9cd06e1c01f728816f4b99f42b6b8fd088da' 
  AND token = 'lCj6Cy+FK5lvRoMB67sBkyopj7tckdqWSbu9x/Bp/DM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}