SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '200d532fe35b78218bfdfd543e13e335a42afb7b1812fe1c14766a2129093595' 
  AND token = '+9m2bASf0/GysIcejSGBf4sgVEYYqi+XlbKE/2TSqjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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