SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63c23cc16bf6a3013899b5254f48f3e8696afb6414d89e37d3bf585d1cffd687' 
  AND token = 'fCKevtYijE/yRWF4OxXsnSj5ENLmShgzMfEccUYr3Ms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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