SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b777611188b0adba6d9721f9f816cc4c3181c31555927a28f81949205032af43' 
  AND token = '2y9s8vYbK8w3wQ1RTqpVtx5FLHyS8jbAoDSR9QLjHG0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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