SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7abe7ce78b44fe7008184a21d82df3535200d1bb9d959bdb3a048763b4d167b3' 
  AND token = 'xVISnxO3XPVhmt+azT8SfMG8e39FzEfZGo6RKA265ug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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