SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3f519bf64e9dc8a396babd6313bc041569f5fd1c5beb6afb240b11eb6f0d6ef9' 
  AND token = 'B197DDxP1n1bKyZWV2JMOWqSP/qtDupA1LMWjJqW2Yg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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