SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5db2399513036a7942ac1b86a037ada27010cb9ff9987f445b4b20a447b70de1' 
  AND token = 'I9qBEVtmzaUuzfuclnCQn8f3NOR6i9zIPFafP4X2JrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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