SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c698374b1d27e09e3534fe4f6a2687f6fe96bfa4c38fb783758d3f407c69b746' 
  AND token = 'glpBN+ru1cN2XSVEhv8LP0MVQXAMDc9wgQNy2b98V+c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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