SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4276d4b0fb023be131400630356b7e9c8cdde50b33bddbf568b0bcfabdfce841' 
  AND token = 'YVtaCPhtoYErjyB6U5rOmpeF6svXhIqM/m7rsKufPLs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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