SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea197fcd5b83d4de3ff249349e61bdfb19eb797cc8d5c5e29f0645a80f3c70b3' 
  AND token = '2ZR6PKRY6cMtjMwxV4nB8pT2iG/EqOkDfLzHPtbcues=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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