SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3f3bd8a92dffe3d756b59557b4bf84aaa7a280f891b0b681b24459e522ad522' 
  AND token = 'zEn3PKwjavr2YCmlT6LP+CbmUm3jJMfhYTdVQFznqok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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