SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91c672541f624780e1cdfc0e174dc9bf898e71386989b56dddb4ef7ee5f548d4' 
  AND token = 'BfxdeQaVtUv4X4JqwrgaZFi+GKvLUeHwjes8L54hxD0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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