SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14cf08a0fe62afb94372106b180e2d49950c8bc53c2ddb9056e7def8363cd407' 
  AND token = 'MEimEiImPx6u32NR0CZvZasbBcZRR/x2AzSHw+u/oow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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