SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17a57350ad63f516a5e74711f7e5dcbb32bd2c9b1f668bf8199729b9c1f74358' 
  AND token = 'BpgULYWtNlWRZuw7osCPg8PJQWyDs9dGPErIsw9Has8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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