SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5f83d4847785f0c0046a33a67c77b1f134a0e2ba89787e863fd81ddffc73c33' 
  AND token = 'MUTgF+pPXNEmbU3jBZUHUy5aX2bF3ffbgLCijMYUtac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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