SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7b3071059e4be814654c8af98f1e2b1dee800b9d5ab5dfd7c65440627338511' 
  AND token = '7BPz+RIfjidlZMg3S1v36uuMLDvkcqbrUZsVHKt2dqU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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