SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea47857ebeb9a45f1f151a17fb7fb79185a8c2038805a5e21ce5ea946138717e' 
  AND token = 'rpmmEM5855kgiZjrNb7szV1TS0U56jM189j51B5Wuuo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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