SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4e657ed4e9bce2d7510540890d5e5de5de24be698cc7e9d722626cb228d4e09' 
  AND token = 'g4zY9HRrnrzkxjKdpAiPhWXAWit4UKwblA6MT0RR1kI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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