SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aecd06469422a1bf0d15b4d296ac845994518644188b0451d5edc848b665ef70' 
  AND token = 'g+eBCi/JxlOLAryzwjStoOR4zrGFPy0uvkoJWYmZTuU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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