SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d315fdcb2c356e840fbd358d847d0b8b63787cfe2a27ffe393de9db402984a1' 
  AND token = '0IqqSNCEujYIaw+5u9W66yvGlhOUgR0g6FczRj7ZT2Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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