SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a912dfd9f400d16ac0a1707ebcc8bb0368b19f5cfff4730d8091d038caca9edd' 
  AND token = 'nCDvnF4tKnhNi4OGsKNda2nz4n+3E9Q/7lEzYQJvjas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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