SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45ac748f636521099032e8aebab0a52627a4d0a82534611695c7a3a1bd6efa43' 
  AND token = 'WPR5CwwrTeJGBiYYKGDdz1uTreh1nVayBi/dS5NMlUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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