SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ea650d4020883a1fc3fe0b5580d705fd7c8a7e93c6e01af1e95172751ee3bc1' 
  AND token = 'xyzUa7PbnyN0A1myMH4R4nvm+qEGOhzdOjaPkdZfmz4=' 
  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"
    }
  }
}