SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '1e6c7b8b56704ef605f672f67ced5bf88f1db1a0c5abc2e859a74a5172d23250' 
  AND token = 'KYJTtSya7UHX7NrElixZnwqwkHE6+mx3GZp/C3whRGY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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