SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '492ac5de71673346e320038c22a1bf13a71396dba9863a3fc90fe83f3571dd6b' 
  AND token = '4kGTCJuDmzDUFWxIAJ7RVvTq9X6piSuQqZhSjKn6BFs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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