SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57e4392068be846238836d5080decf944f57120d067f1b96df2e15ef8e6fec45' 
  AND token = 'Fg8U8C436t67jhddCsMA9XwlqjzUMGMMEcYvZmjB1wQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}