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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6575caf6a64ad5638075cb67e03379d314935a3501e4f5b1d45906aa8c6ce59' 
  AND token = 'PJQCG5VJiLjW5LxvvaqffJ75rrD5AXlxr4tQsrn+bNc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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