SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28ea9733e4df73aef67ade343820e2a6216b1dfd45277417951c05e89565f01e' 
  AND token = '4DleSmrV2ejbG/EVtTMG10+9unFKm8eLCtauYsjZLt4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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