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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd2c7b051e6e78e614face8b3291d5b0c48e097d5fc2b784dc4fddc6e34a73209' 
  AND token = 'CwAW1iHfO51dtPriSNzReofmJJKzCQ+uKQzIy/Mf1vE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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