SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10fc31aa1ab465d22c801ac2796b40432f449ab75f2b48992da3d7581013c2b5' 
  AND token = 'u4vWmPhr2g14PB/suG4gauPI0Zbnr990MkhToNUGW7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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