SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee88ee637def9a6dd925eec32825e28f39e32d044e1ef8b9df8f08d5f2551bf0' 
  AND token = '6/G1+aq6vtCAVPjWcrsm/HChRRB9KncxCIldx3XFtlY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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