SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6fa5dcec3a7114e550427bbb727cba7ea803fcc80cb72c13bcad06464e81b541' 
  AND token = 'arfShPeJuv+6unQiwjRn5RV7TrMBni+tWpMvHrS0Kgw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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