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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c5b54c082371f56cf67ef4f877fa931ab2153928c2ce42dad7eb7dc13fd0f6e4' 
  AND token = 'o72Tc+TK2IGrQl8+fGByG6e+31bCeb3ANTeDZMc2ld4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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