SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb4d6808da429eca9df0388cf4541f269c87533907e4e57ab8f18a403d6e422b' 
  AND token = 'pou+ZLQCGhVKemMWUhz7BkFePMRgjACWLEpUxLO9NoM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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