SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28af048ffa78b33598a83464cc4eb2f96c97e35523edc34691210971fb68ab7c' 
  AND token = 'SpogtDKAmRqmAw0TfrzsDEglr6CgPyyq6UMH6eccS3Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}