SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ef856161ed622a4c11bbe49882bcc549ff7d3e8bc9eda85e2fc9b628456d86f' 
  AND token = 'Vqe0t0GGd+mOrprlwW7fYlx7hKXY7t/DF2pYPEbS0fQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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