SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f98121f6fee132f262329c519dcd758ce804299eb638e6590f087edafeec2588' 
  AND token = '1iSDYdVMhRGVV+oou3+JugH00hzUzhAr+Y6uJLvwgeg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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