SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7e59a7880f4b1ddb977e1a574578af10095cd6abcaf306c39790341d9caa073' 
  AND token = '1qXQMMcjAKkHZRjPVBPejVqp/vl84BhTFKv+VG34uTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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