SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89535d122eb6216d43f0a64af034f8992efe382e63963fd827f6d6d067ba5efa' 
  AND token = '1uzCDVHbpYIhXWEQ6uFW/WAcDTMOX8gNc9IfTyp4VZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00068

JSON explain

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