SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3a1695122eccec7531341f37eb46ebe3d55167d77a848c897679ae8c52ca757' 
  AND token = 'alcMVqwRqh5dmy0807OtVhXSBP/zYVncfMmqi5fpHkk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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