SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '7bde319e051b57f7cf5eda10b2905d4fb241a870031a2d503eec7008b68b44fe' 
  AND token = 'boTkvl0RtZsOdHT0n36mpCfz/CyZRooN6b/BpdtmHFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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