SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '595f1045a9393bb3a53b291e14d7df870cad1fa2895ec67d393197e584be7494' 
  AND token = 'OLVAz1i9QukjBOsXw3J/i7dBkGmM5ijqmP8vBrFbhHw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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