SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a14405485e5b74478ae176e396f4ed8dabfe899bd27e523a1033637decdaad2a' 
  AND token = 'CYQw7RgUeGhsbEfzjNAIre+XjjOg6u8YLU4VWgXYobI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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