SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9aa661179c831872f3e58495e527b7eba2346bef62234b6655a8c08addd04c30' 
  AND token = 'f3+st4vEUDwwNORtsBHGYFrXT6YqcWXnLuDetkOdVjQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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