SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0494215f06712b6dacd6d50119fe7edf9546d893ef11453096024c23feef6c51' 
  AND token = 'MxFpoJ2LRO6cPacbaLfKRXWjnlzxEwdHxvktjvfG4Ec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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