SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cefd287b0c7e870d9c728505a1a30b6327cc2b43e87d6b265daacfe5d0948ca' 
  AND token = 'VrM+q1GoECgGARzjkJXI+CxLwjXJ+wYGm39oerjCUIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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