SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5108877b0ef7913ba5fabff646bee475612ba0f4bd7fb9a462801944d4771d13' 
  AND token = 'ptx+OIrF73SLHO/poc1L6zzgtiilEO0fJuIzLCNdTX8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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