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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '79fcb5e19aed325631aa5e78721e2ccb3c37bb8e6df7236162419e7aa9dcec22' 
  AND token = 'pHZSNM7r1ua199ocfB63oBD0/rBlqUAo0ju5K3e+MVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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