SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e18f9217db3507a351ab3e1a2566438f1b593df5c6a0a7c7bf16552cf744430' 
  AND token = 'qMwzrlATY0JurlpgcsV3i4vahfNh66GiuRjsihFtybw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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