SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e63a160b9261202486070e2ea862af6a2a06ed93d4bf095df397c1ee5938887' 
  AND token = 'VgH/hUO9zRdpnNiMq6vikfEMfQwPHGfELz2tkiEFISs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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