SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e908bc1a42fa854762a74e69533afbf6251f8e12cdad8796feb7d5a95f2fcfe' 
  AND token = 'CzoV/8pkIS7wYQg7dxh6O2Pv4jRJgHmekZd+/ROnC7I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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