SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d402c98b294cb63664b875adbf17bd1a0713a2a17e0b79d4173f8e9538c9890' 
  AND token = 'sCDjSPVW6IxLvK2nVJg3ABWW/pNybi7dOrYS7ULw9J4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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