SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '512005bc4ecb7dd0e1abb35c14e8364552ed9219100612fc81ce5cc5d80d7080' 
  AND token = 'SjbC9K+bL5EZvOFxlKGeadgyM75F9hrCq/At4cgXYgM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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