SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '808384aa93991c837a015b2a0f50a47e37300f00ffaefccabda42bce91467282' 
  AND token = 'MOrRjpElGJLd5vnRSFRHT9ttaNWoy6Ch8zdksezq93w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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