SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35e531e7814e38b26d4567aa5acdad11df3f2222d7224db8c6011876400bef31' 
  AND token = 'NnDHMNuOKLywjjxN1NiH+Wc1EY3E3IOOsfJxGAlSqCc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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