SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf8cbef538f5236085dff6a8424ce826c3ab91099bf79a2ba04ec623160352b6' 
  AND token = 'LWKqAPeWyQgseDo18YM/xxraDgMdFLXZytYQhzkYjaY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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