SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '176d58a5a009cef233d6eb21d9822be383bea764a936dc8a6082f49332949ef4' 
  AND token = '97BWKqqBsXe9znwlM7ROhA3AuOPshNrv6g9TlgQCmjg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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