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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd374dc9857bf17e71ad6ae1a4122f819fd35b3bc78e4a9e31e0d7b6f1486c4e' 
  AND token = 'P6NEvAfOXVsmZPVHZf4khuyaY4asWCCV8RArevK6P1U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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