SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd6e0b4bae35499164415a0e4bf6b0a7c09ee5070ec274707242228bc61bbc61' 
  AND token = 'WjHlETODNh1ZCo1qOjjURcmpOzg0TCveJH3kiKxUzjs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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