SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd1eea9a6db18ea433e3b2f2a34aad4e432d2690401ac1a8a0d4f03beac3131d' 
  AND token = 'PZYCrcnmNKNCA/RKDudh9PbONQF863L6kbTaDI78fWo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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