SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '383605a67c79f15acd3ef870d1577ff525572bf68977794e461e12e14bfe3466' 
  AND token = 'F0rYgZ7D4JYg4ASHEikD1+KwHA0xZ6DoLAlOsifPvCs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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