SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c84e9e88566c358a23ebfd80a59bacb0de4925b2709a104fc2c8c4455b8328d3' 
  AND token = 'pJWVXchJW6irC3dHTZZBy8wnNAH0HHxbyugpXUCbPB0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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