SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d6e3e131f96654dd09b0e5c33a565ef94284aa987282460d2fa8a89816627f7' 
  AND token = 'cQG8zXevZdlwoRpK3jKsT7k5rfOb6xo6YV2j9mNuJ9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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