SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44bbf690ebee87804df79e0b89d6287ff61a399c58a98a586451199ef63b9b32' 
  AND token = '3AiCzwh+mGUhXFdiDj2lhGk9u/cCkvvOPKpmGtiYUsY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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