SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '966a93952ba062ac5da60e940bacb13192922c85c41e60304853c099aac312b8' 
  AND token = 'UV7a2YCEZ4VgEbWeANr2WYwfJWxqo/spCXc2v2gEJOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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