SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf31e18dba55f079a2d88e51d2c5243c7f3065c57cb92caac5f509467fea8bfe' 
  AND token = 'ufVSdvELBr8Q3bj+yzVpHpzlJyeAqdVKkBjJ2SweNJA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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